The objectives of the project are to determine whether emotional relationships in infancy are predictive of later psycho-social adaptation; and to investigate the role of significant intervening experiences. In particular the study focuses on relations between infant-parent attachment and socio-emotional and cognitive development during childhood. Several measures of the mother-infant relationship have been obtained at the beginning of the child's second year. For one subsample father-infant relationship measures were also obtained. Measures of environmental experience, especially substitute childcare and potentially stressful life-events, are collected semi-annually through the child's fourth birthday. Assessments of developmental status begin at age two and continue, semi-annually, until age four. The relative impact of attachment and environmental factors on developmental outcome can be determined contemporaneously at different ages or longitudinally over the course of early development.